What makes Skyrim so special? Why do you keep going back?

What makes this game so good from a game development perspective? Maybe I'm a boomer who is too set in his ways to get into new games, but I have gotten back into this game every few years since I first got the game in middle school and some my finest gaming memories as well as my wife's have come from Skyrim. What is the secret sauce? What makes this game so special to you?

My theory is its the immersion. When I first played Skyrim I was more used to complex RPG style games with combos, damage, and so forth. So when I played Skyrim and clicking the right trigger meant you swing with your right hand just felt so simple and realistic. The world is so vast, gorgeous, and just feels so... lived in. You can see the bandits food, sleeping quarters, and so forth every time you raid one of their dungeons. The shopkeepers and taverns just feel so homey, even with the cheesy NPC catchphrases (Some people call this junk. Me? I call it treasure.) Compared to similar games it puts a lot more emphasis on the role playing part of an RPG - less worrying about stats, combos, etc.